This is B-roll video of POV Polar Bear Collar Cam B-roll 2019, 2021, and 2022.
Health and Energetics of Polar Bears Active
Research in this focal area is centered on (i) collecting data on a variety of systems that help determine and mediate polar bear health and energetics, and (ii) developing monitoring and surveillance programs for detecting changes in population health over time. Additionally, this work will allow us to develop an understanding of how polar bear populations will respond to a variety of stressors modulated by climate change, including contaminant and pathogen exposures, changes in food web structure and prey accessibility, and changes in spatial distribution.
Return to Ecosystems >> Marine Ecosystems >> Polar Bear Research
Effects of declining sea ice on polar bear energetics
Recent declines in sea ice have been linked to reductions in body condition, survival, and population size of polar bears (Ursus maritimus). Reduced access to prey is hypothesized as the primary mechanism of sea-ice linked declines, but polar bears may also experience increased energy expenditure as they respond to changing sea ice composition and extent and prey distributions. As a result, information on the degree to which polar bears can balance food intake with energetic costs has become increasingly important.
A recently published study from this work found that metabolic rates of polar bears were 1.6 times higher than previously assumed. Importantly, this study also documented that low predation success by adult female polar bears in the Beaufort Sea during the spring coupled with high energetic costs resulted in a loss of ≥10% body mass of an 8-11 day period. Spring is typically a period of increasing body mass for polar bears, particularly for females that spent the previous 4 months or more denning and have additional energetic costs to lactate for their cubs.
Linking changes in nutritional ecology to individual- and population-level consequences
Although polar bears could be affected by declining sea ice habitat in a variety of ways, the primary way in which sea ice loss is expected to affect polar bears is by reducing foraging opportunities. Polar bears may experience fewer hunting opportunities if sea ice is reduced to the point of limiting access to their primary prey, ringed seals (Phoca hispida), or if ringed and bearded seals (Erignathus barbatus) respond to sea ice loss by spending more time in open water and less time hauled out on ice, or if changes to sea ice affect reproduction and survival in seal populations. Prey populations may change in abundance and distribution altering the composition of polar bear diets or changing total food intake. Bears may spend less time on the sea ice and more time in terrestrial habitats where the availability of marine mammal carcasses may be a determinant of body condition and reproduction, or they may respond to declining food availability by conserving energy through resting and reducing their metabolic rate. In total, the long-term consequences of changes in foraging ecology associated with a changing Arctic will depend on limits in physiology and behavioral plasticity. In the short-term, behavioral plasticity and ecosystem productivity may be important factors that determine the variation in bear responses.
Risk factors of exposure to contaminants and pathogens
Health is a difficult concept to articulate and measure, but it’s critically important to understand: an animal’s health reflects the interaction between its behavioral choices and the environment. A warming climate has the potential to drive profound changes in the health of Arctic fauna including polar bears. We are collecting data on a variety of systems that help determine polar bear health and using those data to develop monitoring and surveillance programs for detecting changes in population health over time. Additionally, this work is allowing us to develop a deeper understanding of how polar bear populations will respond to a variety of stressors modulated by climate change, including pathogens, pollutants and contaminants, and food web structure. Identifying and monitoring health-based threats to polar bears was identified as a priority information need by wildlife managers.
Polar bears have been shown to be increasingly spending time on land during the summer in response to sea ice loss. A recent study published from this project found that exposure to some pathogens, including Toxoplasma gondii, was higher for bears that summered on land compared to those that summered on the sea ice. Two pathogens, Toxoplasma gondii and Brucella spp., appeared to increase over time and several new pathogens were observed in polar bears that had not been documented previously. These results suggest that changes in the Arctic marine ecosystems not only have direct effects on polar bear access to food resources and energetic costs, but may also increase exposure risk to pathogens that polar bears had previously not been exposed to.
Below are other science projects associated with this project.
Polar Bear Research
Polar Bear Maternal Denning
Polar Bear Population Dynamics
Distribution and Movements of Polar Bears
This is B-roll video of POV Polar Bear Collar Cam B-roll 2019, 2021, and 2022.
Below are publications associated with this project.
Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity
Environmental and behavioral changes may influence the exposure of an Arctic apex predator to pathogens and contaminants
- Overview
Research in this focal area is centered on (i) collecting data on a variety of systems that help determine and mediate polar bear health and energetics, and (ii) developing monitoring and surveillance programs for detecting changes in population health over time. Additionally, this work will allow us to develop an understanding of how polar bear populations will respond to a variety of stressors modulated by climate change, including contaminant and pathogen exposures, changes in food web structure and prey accessibility, and changes in spatial distribution.
Return to Ecosystems >> Marine Ecosystems >> Polar Bear Research
Effects of declining sea ice on polar bear energetics
Recent declines in sea ice have been linked to reductions in body condition, survival, and population size of polar bears (Ursus maritimus). Reduced access to prey is hypothesized as the primary mechanism of sea-ice linked declines, but polar bears may also experience increased energy expenditure as they respond to changing sea ice composition and extent and prey distributions. As a result, information on the degree to which polar bears can balance food intake with energetic costs has become increasingly important.
A recently published study from this work found that metabolic rates of polar bears were 1.6 times higher than previously assumed. Importantly, this study also documented that low predation success by adult female polar bears in the Beaufort Sea during the spring coupled with high energetic costs resulted in a loss of ≥10% body mass of an 8-11 day period. Spring is typically a period of increasing body mass for polar bears, particularly for females that spent the previous 4 months or more denning and have additional energetic costs to lactate for their cubs.
Linking changes in nutritional ecology to individual- and population-level consequences
Although polar bears could be affected by declining sea ice habitat in a variety of ways, the primary way in which sea ice loss is expected to affect polar bears is by reducing foraging opportunities. Polar bears may experience fewer hunting opportunities if sea ice is reduced to the point of limiting access to their primary prey, ringed seals (Phoca hispida), or if ringed and bearded seals (Erignathus barbatus) respond to sea ice loss by spending more time in open water and less time hauled out on ice, or if changes to sea ice affect reproduction and survival in seal populations. Prey populations may change in abundance and distribution altering the composition of polar bear diets or changing total food intake. Bears may spend less time on the sea ice and more time in terrestrial habitats where the availability of marine mammal carcasses may be a determinant of body condition and reproduction, or they may respond to declining food availability by conserving energy through resting and reducing their metabolic rate. In total, the long-term consequences of changes in foraging ecology associated with a changing Arctic will depend on limits in physiology and behavioral plasticity. In the short-term, behavioral plasticity and ecosystem productivity may be important factors that determine the variation in bear responses.
Risk factors of exposure to contaminants and pathogens
Health is a difficult concept to articulate and measure, but it’s critically important to understand: an animal’s health reflects the interaction between its behavioral choices and the environment. A warming climate has the potential to drive profound changes in the health of Arctic fauna including polar bears. We are collecting data on a variety of systems that help determine polar bear health and using those data to develop monitoring and surveillance programs for detecting changes in population health over time. Additionally, this work is allowing us to develop a deeper understanding of how polar bear populations will respond to a variety of stressors modulated by climate change, including pathogens, pollutants and contaminants, and food web structure. Identifying and monitoring health-based threats to polar bears was identified as a priority information need by wildlife managers.
Polar bears have been shown to be increasingly spending time on land during the summer in response to sea ice loss. A recent study published from this project found that exposure to some pathogens, including Toxoplasma gondii, was higher for bears that summered on land compared to those that summered on the sea ice. Two pathogens, Toxoplasma gondii and Brucella spp., appeared to increase over time and several new pathogens were observed in polar bears that had not been documented previously. These results suggest that changes in the Arctic marine ecosystems not only have direct effects on polar bear access to food resources and energetic costs, but may also increase exposure risk to pathogens that polar bears had previously not been exposed to.
- Science
Below are other science projects associated with this project.
Polar Bear Research
Polar bears ( Ursus maritimus ) are one of 4 marine mammal species managed by the U.S. Department of Interior. The USGS Alaska Science Center leads long–term research on polar bears to inform local, state, national and international policy makers regarding conservation of the species and its habitat. Our studies, ongoing since 1985, are focused on population dynamics, health and energetics...Polar Bear Maternal Denning
Pregnant polar bears enter maternity dens in October/November, give birth to cubs in December/January, and exit dens in March/April. Historically, most polar bears from the Southern Beaufort Sea (SBS) population constructed maternity dens on the sea ice. Over the last three decades, as sea ice has become thinner and prone to fragmentation, there has been a landward shift in the distribution of...Polar Bear Population Dynamics
Information on the status and trends of polar bear populations are needed to inform management of polar bears under US laws and international agreements. The USGS maintains a long-term research program focused on the population dynamics of the southern Beaufort Sea polar bear population. In addition, the USGS collaborates with the US Fish and Wildlife Service in population studies in the Chukchi...Distribution and Movements of Polar Bears
Polar bears are tied to the sea ice for nearly all of their life cycle functions. Most important of these is foraging, or access to food. Polar bears almost exclusively eat seals, and they are equally as dependent upon the sea for their nutrition as are seals, whales, and other aquatic mammals. Polar bears are not aquatic, however, and their only access to the seals is from the surface of the sea... - Multimedia
POV Polar Bear Collar Cam B-roll 2019, 2021, and 2022POV Polar Bear Collar Cam B-roll 2019, 2021, and 2022POV Polar Bear Collar Cam B-roll 2019, 2021, and 2022
This is B-roll video of POV Polar Bear Collar Cam B-roll 2019, 2021, and 2022.
This is B-roll video of POV Polar Bear Collar Cam B-roll 2019, 2021, and 2022.
- Publications
Below are publications associated with this project.
Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity
The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consumeAuthorsKaryn D. Rode, Ryan H. Wilson, David C. Douglas, Vanessa L Muhlenbruch, Todd C. Atwood, Eric V. Regehr, Evan Richardson, Nicholas Pilfold, Andrew E. Derocher, George M. Durner, Ian Stirling, Steven C. Amstrup, Michelle St. Martin, Anthony M. Pagano, Kristin S. SimacEnvironmental and behavioral changes may influence the exposure of an Arctic apex predator to pathogens and contaminants
Recent decline of sea ice habitat has coincided with increased use of land by polar bears (Ursus maritimus) from the southern Beaufort Sea (SB), which may alter the risks of exposure to pathogens and contaminants. We assayed blood samples from SB polar bears to assess prior exposure to the pathogens Brucella spp., Toxoplasma gondii, Coxiella burnetii, Francisella tularensis, and Neospora caninum,AuthorsTodd C. Atwood, Colleen G. Duncan, Kelly A. Patyk, Pauline Nol, Jack Rhyan, Matthew McCollum, Melissa A. McKinney, Andrew M. Ramey, Camila Cerqueira-Cezar, Oliver C H Kwok, Jitender P Dubey, S.G. Hennager